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Mercedes-Benz has kicked off a high-stakes bid for electric performance car supremacy with the unveiling of the production version of the SLS AMG Coupe Electric Drive at the Paris motor show. Priced at the equivalent of $540,000 in Germany, including a 19 percent sales tax, it is Mercedes-Benz's most expensive road car to date.

Described as the world's most powerful series production electric car, the SLS Electric Drive shares its exterior styling, including signature gullwing doors, with the gasoline-engined SLS AMG introduced in 2009. Apart from some small changes to the styling of the grille insert, the biggest clue to the car's electric driveline is the absence of exhaust pipes.

The SLS Electric Drive uses a high-tech driveline consisting of four synchronous electric motors—one at each corner—providing it with permanent four-wheel drive. The electric motors, each weighing 99 pounds, deliver a total of 740 hp and 738 lb-ft of torque. That's 177 hp and 259 lb-ft more than the 6.2-liter V8 in the standard SLS AMG.

For comparison, the electric-powered Audi R8 e-tron, which is expected to cost about half the price of the new Mercedes-Benz when it goes on sale in early 2013, packs a claimed 376 hp and 604 lb-ft.

The electric SLS AMG is equipped with two separate gearboxes that provide direct drive to each axle, along with a new AMG Torque Dynamics system that provides selective drive to individual wheels depending on prevailing traction in three different modes—Comfort, Sport and Sport Plus. Mercedes says the car will reach 62 mph from standstill in 3.9 seconds and is electronically limited to a top speed of 155 mph.

By comparison, the standard SLS AMG reaches 62 mph in 3.8 seconds and has a top speed of 197 mph.

The driver can call up what Mercedes-Benz describes as a typical AMG sound tailored for each driving situation with the press of a so-called “power” button. The synthetic sound is played through 11 speakers located around the cabin.

Energy for the electric motors is provided by a 60kWh lithium-ion battery pack developed in cooperation between Mercedes-Benz's AMG performance car division and its British-based High Performance Engines offshoot. The British unit developed the 2.4-liter V8 Formula One engine and KERS (kinetic-energy-recovery system) unit used by the Mercedes-Benz, McLaren and Force India teams.

The liquid-cooled battery, which weighs 1,208 pounds, is mounted within the transmission tunnel down the center of the cabin and behind the driver and passenger seats in the space filled by the fuel tank in the standard SLS AMG. The battery consists of 12 individual modules, each comprising 72 cells. The cells are supplied by Korean-based company SK Innovation.

A full charge on standard 230-volt European power takes up to 20 hours. This can be reduced to three hours using an optional wall box, which provides a 22kW quick charge. As in Formula One racing, the battery is also charged on the run by recuperated energy created under braking and during in-gear coasting. The driver can alter the level of energy that is recovered via steering-wheel mounted paddles.

To offset the weight of the battery, AMG has introduced lightweight construction for the SLS Electric Drive, eschewing the aluminum structure of the standard model for a more advanced aluminum and carbon-fiber arrangement first revealed at last year's Frankfurt motor show. Other weight-saving measures include standard carbon-fiber ceramic brake discs measuring 15.8 inches up front and 14.2 inches at the rear.

To accommodate the drive being direct to the front axle, AMG has redesigned the front suspension with the double-wishbone system making way for a pushrod arrangement using horizontally mounted dampers and springs. The steering also eschews the existing hydraulic assist for a new speed-sensitive electro-hydraulic system. The standard wheels are 19 inches with 265/35 profile tires up front and 20 inches with 295/30 profile at the rear.

The 2012 Paris motor show—or Mondial de l'Automobile, as it is officially known––will take place Sept. 27 through Oct. 14. It occurs every two years, alternating with the Frankfurt motor show in Germany. Paris is a showcase for the latest in design, but automakers will also be showing off their latest concept cars, green cars and supercars.